Time-gated delay lock loop tracking of digital television signals

• US 20020135518A1
• Filed: 01/22/2002
• Published: 09/26/2002
• Est. Priority Date: 02/02/2001
• Status: Abandoned Application

• Current Assignee: Rosum Corporation (Liberty Broadband Corp.)
• Original Assignee: Rosum Corporation (Liberty Broadband Corp.)
• Inventors: Rabinowitz, Matthew, Spilker, James J. Jr.
• Application Number:
  US10/054,262
• Publication Number:
  US 20020135518A1
• Time in Patent Office: Days
• US Class Current: 342/464
• CPC Class Codes: A63F 2300/205 for detecting the geographical location of the game platform
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0054 of actual mobile position, i.e. position calculation on base station
• CPC Class Codes: G01S 5/0081 Transmission between base stations
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0221 Receivers
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 5/145 Using a supplementary range measurement, e.g. based on pseudo-range measurements
• CPC Class Codes: H04N 21/25841 involving the geographical location of the client retrieval from the Internet by querying based on geographical locations G06F16/9537; arrangements for identifying locations of receiving stations in broadcast systems H04H60/51; location of the user terminal in data switching networks H04L67/52; services making use of the location of users or terminals in wireless networks H04W4/02; locating users or terminals in wireless networks H04W64/00
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/2668 Creating a channel for a dedicated end-user group, e.g. insertion of targeted commercials based on end-user profiles information retrieval from the Internet by querying with filtering and personalisation G06F16/9535; arrangements for replacing or switching information during the broadcast H04H20/10; push services over packet-switching network H04L12/1859; adaptation of message content in packet-switching networks H04L51/063
• CPC Class Codes: H04N 21/41422 located in transportation means, e.g. personal vehicle arrangements specially adapted for transportation systems in broadcast systems H04H20/62
• CPC Class Codes: H04N 21/615 Signal processing at physical level signal processing in analog two-way television systems H04N7/173
• CPC Class Codes: H04N 21/8126 involving additional data, e.g. news, sports, stocks, weather forecasts

Abstract

A computer program product, apparatus, and method for use in determining the position of a user terminal includes receiving at the user terminal a digital television (DTV) broadcast signal transmitted by a DTV transmitter; tracking a periodic component of the DTV signal using a delay lock loop (DLL), including selecting an observation interval based on the timing of the periodic component, and turning on a portion of the DLL during the observation interval, and turning the portion off otherwise; and determining a pseudo-range between the user terminal and the DTV transmitter based on the DTV broadcast signal; and wherein the position of the user terminal is determined based on the pseudo-range and a location of the DTV transmitter.

Claims

1. A method for use in determining the position of a user terminal, comprising:

receiving at the user terminal a digital television (DTV) broadcast signal transmitted by a DTV transmitter;

tracking a periodic component of the DTV signal using a delay-lock loop (DLL), including

selecting an observation interval based on the timing of the periodic component, and

turning on a portion of the DLL during the observation interval, and turning the portion off otherwise; and

determining a pseudo-range between the user terminal and the DTV transmitter based on the DTV broadcast signal; and

wherein

the position of the user terminal is determined based on the pseudo-range and a location of the DTV transmitter.

2. The method of claim 1, further comprising:

determining the position of the user terminal based on the pseudo-range and the location of the DTV transmitter.

3. The method of claim 2, wherein determining a position of the user terminal comprises:

adjusting the pseudo-range based on a difference between a transmitter clock at the DTV transmitter and a known time reference; and

determining the position of the user terminal based on the adjusted pseudo-range and the location of the DTV transmitter.

4. The method of claim 1, wherein the DTV broadcast signal is an American Television Standards Committee (ATSC) DTV signal, and the pseudo-range is determined based on a known digital sequence in the ATSC frame.

5. The method of claim 4, wherein the known digital sequence is a synchronization code.

6. The method of claim 5, wherein the synchronization code is a Field Synchronization Segment within an ATSC data frame.

7. The method of claim 5, wherein the synchronization code is a Synchronization Segment within a Data Segment within an ATSC data frame.

8. The method of claim 1, wherein determining a position of the user terminal comprises:

determining an offset between a local time reference in the user terminal and a master time reference; and

determining the position of the user terminal based on the pseudo-range, the location of the DTV transmitter, and the offset.

9. The method of claim 1, wherein determining a pseudo-range comprises:

correlating the DTV signal with a signal generated by the user terminal as the DTV signal is received to produce the pseudo-range.

10. The method of claim 1, further comprising:

tracking the pilot signal of the DTV signal using a phase-lock loop; and

wherein

tracking the component of the DTV signal is based on the tracking of the pilot signal.

11. The method of claim 1, further comprising:

transmitting the pseudo-range to a location server configured to determine a position of the user terminal based on the pseudo-range and a location of the DTV transmitter.

12. The method of claim 1, wherein the position of the user terminal is determined by adjusting the pseudorange based on a difference between a transmitter clock at the transmitter of the broadcast analog television signal and a known time reference, and determining the position of the user terminal based on the adjusted pseudorange and the location of the TV transmitter.

13. The method of claim 1, further comprising:

determining a further pseudorange based on a further DTV signal; and

projecting the pseudorange and the further pseudorange to an instant of time, thereby eliminating any first order term in the clock of the user terminal.

15. The media of claim 14, wherein the method further comprises:

determining the position of the user terminal based on the pseudo-range and the location of the DTV transmitter.

16. The media of claim 15, wherein determining a position of the user terminal comprises:

adjusting the pseudo-range based on a difference between a transmitter clock at the DTV transmitter and a known time reference; and

determining the position of the user terminal based on the adjusted pseudo-range and the location of the DTV transmitter.

17. The media of claim 14, wherein the DTV broadcast signal is an American Television Standards Committee (ATSC) DTV signal, and the pseudo-range is determined based on a known digital sequence in the ATSC frame.

18. The media of claim 17, wherein the known digital sequence is a synchronization code.

19. The media of claim 18, wherein the synchronization code is a Field Synchronization Segment within an ATSC data frame.

20. The media of claim 18, wherein the synchronization code is a Synchronization Segment within a Data Segment within an ATSC data frame.

21. The media of claim 14, wherein determining a position of the user terminal comprises:

determining an offset between a local time reference in the user terminal and a master time reference; and

determining the position of the user terminal based on the pseudo-range, the location of the DTV transmitter, and the offset.

22. The media of claim 14, wherein determining a pseudo-range comprises:

correlating the DTV signal with a signal generated by the user terminal as the DTV signal is received to produce the pseudo-range.

23. The media of claim 14, wherein the method further comprises:

tracking the pilot signal of the DTV signal using a phase-lock loop; and

wherein

tracking the component of the DTV signal is based on the tracking of the pilot signal.

24. The media of claim 14, wherein the method further comprises:

transmitting the pseudo-range to a location server configured to determine a position of the user terminal based on the pseudo-range and a location of the DTV transmitter.

25. The media of claim 14, wherein the position of the user terminal is determined by adjusting the pseudorange based on a difference between a transmitter clock at the transmitter of the broadcast analog television signal and a known time reference, and determining the position of the user terminal based on the adjusted pseudorange and the location of the TV transmitter.

26. The media of claim 14, wherein the method further comprises:

determining a further pseudorange based on a further DTV signal; and

projecting the pseudorange and the further pseudorange to an instant of time, thereby eliminating any first order term in the clock of the user terminal.

28. The apparatus of claim 27, further comprising:

means for determining the position of the user terminal based on the pseudo-range and the location of the DTV transmitter.

29. The apparatus of claim 28, wherein means for determining a position of the user terminal comprises:

means for adjusting the pseudo-range based on a difference between a transmitter clock at the DTV transmitter and a known time reference; and

means for determining the position of the user terminal based on the adjusted pseudo-range and the location of the DTV transmitter.

30. The apparatus of claim 27, wherein the DTV broadcast signal is an American Television Standards Committee (ATSC) DTV signal, and the pseudo-range is determined based on a known digital sequence in the ATSC frame.

31. The apparatus of claim 30, wherein the known digital sequence is a synchronization code.

32. The apparatus of claim 31, wherein the synchronization code is a Field Synchronization Segment within an ATSC data frame.

33. The apparatus of claim 31, wherein the synchronization code is a Synchronization Segment within a Data Segment within an ATSC data frame.

34. The apparatus of claim 27, wherein means for determining a position of the user terminal comprises:

means for determining an offset between a local time reference in the user terminal and a master time reference; and

means for determining the position of the user terminal based on the pseudo-range, the location of the DTV transmitter, and the offset.

35. The apparatus of claim 27, wherein means for determining a pseudo-range comprises:

means for correlating the DTV signal with a signal generated by the user terminal as the DTV signal is received to produce the pseudo-range.

36. The apparatus of claim 27, further comprising:

means for tracking the pilot signal of the DTV signal using a phase-lock loop; and

wherein

means for tracking the component of the DTV signal is based on the tracking of the pilot signal.

37. The apparatus of claim 27, further comprising:

means for transmitting the pseudo-range to a location server configured to determine a position of the user terminal based on the pseudo-range and a location of the DTV transmitter.

38. The apparatus of claim 27, wherein the position of the user terminal is determined by adjusting the pseudorange based on a difference between a transmitter clock at the transmitter of the broadcast analog television signal and a known time reference, and determining the position of the user terminal based on the adjusted pseudorange and the location of the TV transmitter.

39. The apparatus of claim 27, further comprising:

means for determining a further pseudorange based on a further DTV signal; and

means for projecting the pseudorange and the further pseudorange to an instant of time, thereby eliminating any first order term in the clock of the user terminal.

14. Computer-readable media embodying instructions executable by a computer to perform a method for use in determining the position of a user terminal, the method comprising:

receiving at the user terminal a digital television (DTV) broadcast signal transmitted by a DTV transmitter;

tracking a periodic component of the DTV signal using a delay-lock loop (DLL), including

selecting an observation interval based on the timing of the periodic component, and

turning on a portion of the DLL during the observation interval, and turning the portion off otherwise; and

determining a pseudo-range between the user terminal and the DTV transmitter based on the DTV broadcast signal; and

wherein

the position of the user terminal is determined based on the pseudo-range and a location of the DTV transmitter.

27. An apparatus for use in determining the position of a user terminal, comprising:

means for receiving at the user terminal a digital television (DTV) broadcast signal transmitted by a DTV transmitter;

means for tracking a periodic component of the DTV signal using a delay-lock loop (DLL), including

means for selecting an observation interval based on the timing of the periodic component, and

means for turning on a portion of the DLL during the observation interval, and turning the portion off otherwise; and

means for determining a pseudo-range between the user terminal and the DTV transmitter based on the DTV broadcast signal; and

wherein

the position of the user terminal is determined based on the pseudo-range and a location of the DTV transmitter.

40. An apparatus for use in determining the position of a user terminal, comprising:

an antenna to receive at the user terminal a digital television (DTV) broadcast signal transmitted by a DTV transmitter;

a receiver to track a periodic component of the DTV signal using a delay-lock loop (DLL), including a controller to

select an observation interval based on the timing of the periodic component, and

turn on a portion of the DLL during the observation interval, and turning the portion off otherwise; and

a processor to determine a pseudo-range between the user terminal and the DTV transmitter based on the DTV broadcast signal; and

wherein

the position of the user terminal is determined based on the pseudo-range and a location of the DTV transmitter.

41. The apparatus of claim 40, wherein the processor determines the position of the user terminal based on the pseudo-range and the location of the DTV transmitter.

42. The apparatus of claim 41, wherein the processor:

adjusts the pseudo-range based on a difference between a transmitter clock at the DTV transmitter and a known time reference; and

determines the position of the user terminal based on the adjusted pseudo-range and the location of the DTV transmitter.

43. The apparatus of claim 40, wherein the DTV broadcast signal is an American Television Standards Committee (ATSC) DTV signal, and the pseudo-range is determined based on a known digital sequence in the ATSC frame.

44. The apparatus of claim 43, wherein the known digital sequence is a synchronization code.

45. The apparatus of claim 44, wherein the synchronization code is a Field Synchronization Segment within an ATSC data frame.

46. The apparatus of claim 44, wherein the synchronization code is a Synchronization Segment within a Data Segment within an ATSC data frame.

47. The apparatus of claim 40, wherein the processor:

determines an offset between a local time reference in the user terminal and a master time reference; and

determines the position of the user terminal based on the pseudo-range, the location of the DTV transmitter, and the offset.

48. The apparatus of claim 40, wherein the processor correlates the DTV signal with a signal generated by the user terminal as the DTV signal is received to produce the pseudo-range.

49. The apparatus of claim 40, further comprising:

a phase-lock loop to track the pilot signal of the DTV signal; and

wherein

tracking the component of the DTV signal is based on the tracking of the pilot signal.

50. The apparatus of claim 40, further comprising:

a transmitter to transmit the pseudo-range to a location server configured to determine a position of the user terminal based on the pseudo-range and a location of the DTV transmitter.

51. The apparatus of claim 40, wherein the position of the user terminal is determined by adjusting the pseudorange based on a difference between a transmitter clock at the transmitter of the broadcast analog television signal and a known time reference, and determining the position of the user terminal based on the adjusted pseudorange and the location of the TV transmitter.

52. The apparatus of claim 40, wherein the processor:

determines a further pseudorange based on a further DTV signal; and

projects the pseudorange and the further pseudorange to an instant of time, thereby eliminating any first order term in the clock of the user terminal.